This type of shoe is used, most especially, for skiing, mountaineering, and hiking. In order to adapt the form of the shoe to the anatomical morphology of the foot and ankle, in particular, of each wearer, and in order to ensure that the wearer experiences optimal balance during his activities, mechanisms have already been suggested, which not only allow for variation of the inclination of the shaft in relation to the shell, and thus of the lower leg of the wearer, along the transverse axis, but also permit variation of the inclination of that transverse axis along a geometrical axis, whether or not this axis is given material form by stationary end-pieces, said axis extending longitudinally in relation to the shoe. This is the case, most notably, of the adjustment mechanism described in French Patent Application FR 2 433 311.
According to the description contained in this document, the end-pieces of the transverse axis along which the bottom of the shaft is jointed to the shell, may be moved along a guiding mechanism, in such a way that the transverse axis undergoes rotation around an axis which is longitudinal in relation to the shoe. The end-pieces are then locked in position, thus obtaining the proper adjustment. The two end-pieces of the transverse axis may be moved and locked in place along two slots cut in the opposite sides of the shell.
Two general means for ensuring adjustment and locking into position are proposed in this document. In the first, at least one end-piece of the transverse axis is joined to a notched strip which may be moved and secured in place along a series of notches in a paired profile attached to a small plate joined to the shell in which the slots are cut. In the second, which may be combined with the first, a system comprised of a bolt and nut arranged in parallel fashion to the corresponding slot is used; the bolt is stationary in relation to the portion of the axis, and movable in relation to the shell, relative to which the nut is stationary, or vice-versa.
As for the results obtained, these well-known mechanisms are entirely satisfactory. However, the operation of these mechanisms remains relatively long and delicate. Indeed, to adjust properly the position and inclination of the transverse jointing axis, one end-piece of the axis must be moved upward along the slot, and the other end-piece must be moved downward in the corresponding slot. Thus, two adjustment operations must be performed separately and independently, of one an other. Furthermore, it is often necessary make a rough adjustment of position on each side first, before fine-tuning the adjustment at least on one side, all of which the wearer obviously desires to avoid and sometimes does, in fact, neglect, thus compromising his own comfort.
Attempts have been made to eliminate these disadvantages, by proposing devices for adjusting the inclination of the transverse axis longitudinally, by moving nearly vertically in opposite directions the two ends of the transverse axis using a single operation, and, in addition, by ensuring, nevertheless, that the shaft is optimally secured to the base of the shell, whatever the position of adjustment of this shaft on the base of the shell. All of this would be accomplished by using a single means of operating the adjustment mechanism and holding it in position.
Thus, Patents Nos. FR 2 536 966 and FR 2 545 701, as well as Application EP 0 171 384, describe shoes in which the two ends of the transverse axis, i.e., the points where the shaft is jointed to the shell, are joined by a flexible stirrup-shaped piece surrounding, in a transverse plane, the lower part of the wearer's foot, in the region extending from the plantar support to the malleolus, where the hinges joining the shaft to the shell are found. The mechanisms for operating the adjustment of the stirrup and for holding it in place are installed in the thickness of the sole of the shoe. In Patents Nos. FR 2 536 966 and FR 2 545 701, the stirrup is placed between the exterior wall of the base of the shell and the interior wall of the shaft. In Application No. EP 0 171 384, the stirrup is installed in the interior itself of the shell base of the shoe, with which cooperates with an intermediate guiding piece of the stirrup.
Although these arrangements allow the simultaneous movement of the points at which the shaft is jointed to the shell and which delimit the transverse axis, the skier does not have easy access to them when the shoe is mounted on the ski, because they are placed inside the sole. Furthermore, their lateral force, concentrated between the shaft and the shell, provides adequate support in areas that are very small, and where the stress exerted may reach levels that are far too great, indeed even critical.